Do I really need a food scale?

If you are tracking protein at all, it is the highest-leverage cheap tool in the kitchen. Measuring by weight is far more accurate than eyeballing or measuring by volume, and it turns "grams of protein per serving" from an estimate into a fact — a heaping versus level scoop of powder can swing a serving's protein noticeably. On a small appetite the accuracy cuts both ways: it helps make sure enough protein actually lands, not only that portions stay modest. A reliable scale costs about twenty dollars, which is why it anchors the portion-tools category.